Office of the Solicitor Home
DOI Office of the Solicitor

U.S. Department of the Interior
Office of the Solicitor

To access each document, click the link on the Opinion NUMBER column.

1993-present M-Opinion IndexPDF Format  
1/18/2017 M-37045 PDF Format

Reaffirmation of the United States' Unique Trust Relationship with Indian Tribes and Related Indian Law Principles

1/18/2017 M-37044 PDF Format

Opinion Regarding the Status of Mineral Ownership Underlying the Missouri River within the Boundaries of the Fort Berthold Reservation (North Dakota)

1/13/2017 M-37043 PDF Format

Authority to Acquire Land into Trust in Alaska

1/12/2017 M-37042 PDF Format

Suspended and temporarily withdrawn on February 6, 2017
Authority of the U.S. Fish and Wildlife Service to Manage Non-Federal Oil and Gas Activities Underlying National Wildlife Refuges

1/10/2017 M-37041 PDF Format

Suspended and temporarily withdrawn on February 6, 2017
Incidental Take Prohibited Under the Migratory Bird Treaty Act

12/22/2016 M-37040 PDF Format

Reconsideration of the Lumbee Act of 1956

12/21/2016 M-37039 PDF Format

Suspended and temporarily withdrawn on February 6, 2017
The Bureau of Land Management's Authority to Address Impacts of its Land Use Authorizations through Mitigation

12/4/2016 M-37038 PDF Format

Suspended and temporarily withdrawn on February 6, 2017
Tribal Treaty and Environmental Statutory Implications of the Dakota Access Pipeline

6/8/2016 M-37037 PDF Format

Implementation of the Indian Child Welfare Act by Legislative Rule

3/8/2016 M-37036 PDF Format

Twin Metals Minnesota Application to Renew Preference Right Leases (MNES-01352 and MNES-01353)

2/18/2016 M-37035 PDF Format

Partial Withdrawal of Solicitor's Opinion M-36974, Inspector General's Report on Land Acquisitions

1/15/2016 M-37034 PDF Format

Boundary of the Skokomish Reservation along the Skokomish River

1/15/2016 M-37033 PDF Format

Opinion Regarding the Status of the Bed of the Clearwater River within the 1863 Treaty Boundaries of the Nez Perce Reservation (Idaho)

11/20/2015 M-37032 PDF Format

Opinion on the Boundaries of the Mille Lacs Reservation

5/1/2015 M-37031 PDF Format

Legal Status of the Red Lake Band of Chippewa Indians' Restored Lands Assessed for Drainage Works by the State of Minnesota Under the Authority of the Volstead Act of 1908

12/23/2014 M-37030 PDF Format

Trinity River Division Authorization's 50,000 Acre-Foot Proviso and the 1959 Contract between the Bureau of Reclamation and Humboldt County

3/12/2014 M-37029 PDF Format

The Meaning of "Under Federal Jurisdiction" for Purposes of the Indian Reorganization Act

6/21/2013 M-37028 PDF Format

Applicability of the New Mexico Bureau of Land Management's Riparian Policy to Lands within the Boundaries of the Santa Clara Pueblo Grant

6/7/2013 M-37027 PDF Format

Boundary Dispute: Pueblo of Santa Ana Petition for Correction of the Survey of the South Boundary of the Pueblo of San Felipe Grant

8/10/2012 M-37026 PDF Format

Applicability of the Indian Land Consolidation Act's Lien Provisions to the Cobell Settlement

11/04/2011 M-37025 PDF Format

Partial Withdrawal of M-36964 - "Proposed Installation of MCI Fiber Optic Communications Line Within Southern Pacific Transportation Co.'s Railroad Right-of Way"

05/04/2011 M-37024 PDF Format

Withdrawal of M-37013 - The Meaning of "In Danger of Extinction Throughout All or a Significant Portion of its Range."

01/18/2009 M-37023 PDF Format

Applicability of 25 U.S.C. § 2719 to Restricted Fee Lands

01/16/2009 M-37022PDF Format

Protest and Administrative Appeal of Biological Assessments – Livestock Grazing

01/16/2009 M-37021PDF Format

The Meaning of “Foreseeable Future” in Section 3(20) of the Endangered Species Act

01/16/2009 M-37020PDF Format

The Bureau of Land Management’s Authority To Issue Prospecting Permits for Energy Minerals on Bankhead-Jones Farm Tenant Act Lands

01/15/2009 M-37019PDF Format

Revival of Offshore Oil and Gas Leases

12/12/2008 M-37018 PDF Format

U.S. Fish and Wildlife Service Authority under Section 4(c)(l) of the Endangered Species Act to Revise Lists of Endangered and Threatened Species to " Reflect Recent Determinations "

10/03/2008 M-37017PDF Format

Guidance on the Applicability of the Endangered Species Act's Consultation Requirements to Proposed Actions Involving the Emissions of Greenhouse Gases

10/03/2008 M-37016PDF Format

The Secretary's Authority to Exclude Areas from a Critical Habitat Designation under Section 4(b)(2) of the Endangered Species Act

05/23/2008 M-37015PDF Format

Legal Implications Affecting the Importation of Sport-hunted Polar Bears from Canada Resulting from the Listing of the Polar Bear as a Threatened Species under the Endangered Species Act

12/17/2007 M-37014PDF Format

Funding to States and Indian Tribes Under the Surface Mining Control and Reclamation Act of 1977, as Amended by the Tax Relief and Health Care Act of 2006

02/23/2007 M-37013PDF Format

The Meaning of "In Danger of Extinction Throughout Allor a Significant Portion of its Range"

11/14/2005 M-37012PDF Format

Legal Requirements for Determining Mining Claim Validity before Approving a Mining Plan of Operation

11/14/2005 M-37011PDF Format

Rescission of 2001 Ancillary Use Opinion

10/07/2003 M-37010PDF Format

Mill Site Location and Patenting under the 1872 Mining Law

05/13/2003 M-37008PDF Format

Authority for the Bureau of Land Management to Consider Requests for Retiring Grazing Permits and Leases on Public Lands

10/23/2001 M-37007PDF Format

Surface Management Provisions for Hardrock Mining

01/18/2001 M-37006PDF Format

Great Sand Dunes National Park

01/19/2001 M-37005PDF Format

Whether Public Lands Withdrawn by Executive Orders 6910 and 6964 or Established as Grazing Districts are "Reservations within the Meaning of Section 4(e) of the Federal Power Act”

01/18/2001 M-37004PDF Format

Use of Mining Claims for Purposes Ancillary to Mineral Extraction

01/18/2001 M-37003PDF Format

Binding Nature of Solicitor's M-Opinions on the Office of Hearings and Appeals

01/19/2001 M-37002PDF Format

Eastern Boundary of the Sandia Pueblo Grant

01/11/2001 M-37001PDF Format

Proposed New Mexico Standards and Guidelines for Grazing Administration; Evaluation and Recommendations

12/05/2000 M-37000PDF Format

Boundary Dispute Between Santa Ana Pueblo and San Felipe Pueblo: The Secretary’s Authority to Correct Erroneous Surveys, Revisiting Part IV of Solicitor’s Opinion on ‘Pueblo of Sandia Boundary’ 96 I.D. 331 (1998)

12/27/1999 M-36999PDF Format

Regulation of Hardrock Mining

06/09/1999 M-36998PDF Format

Disposal of Mineral Materials from Unpatented Mining Claims

05/22/1998 M-36995PDF Format

Proposed Gaming on the Hatch Tract in Lane County, Oregon, for the Confederated Tribes of Coos, Lower Umpqua and Siuslaw Indians

05/22/1998 M-36994PDF Format

Patenting of Mining Claims and Mill Sites in Wilderness Areas

04/16/1998 M-36993PDF Format

Options Regarding Applications for Hardrock Mineral Prospecting Permits on Acquired Lands Near a Unit of the National Park System

11/19/1997 M-36992PDF Format

Section 3406(b)(2) of the Central Valley Project Improvement Act

09/19/1997 M-36991PDF Format

Whether lands taken in trust for Pokagon Band of Potawatomi Indians should be considered “restored” lands under Indian Gaming Regulatory Act (IGRA)

11/12/1997 M-36990PDF Format

Entitlement to a Mineral Patent Under the Mining Law of 1872

11/12/1997 M-36989PDF Format

Managing Areas Eligible for Protection Under the Wild & Scenic Rivers Act

11/07/1997 M-36988PDF Format

Limitations on Patenting Millsites Under the Mining Law of 1872

12/05/1996 M-36987PDF Format

BLM’s Authority to Recover Costs of Mineral Document Processing

12/05/1996 M-36986PDF Format

Control of Surface Coal Mining Operations Under the Surface Mining Control and Reclamation Act

08/16/1996 M-36985PDF Format

Whether the Circle of Nations Wahpeton Indian School Campus Constitutes Indian Country

03/22/1996 M-36984PDF Format

Excess Reserves Under the Mining Law

02/12/1996 M-36983PDF Format

What are Significant Revisions in the Five-Year Outer Continental Shelf (OCS) Oil and Gas Leasing Program

03/30/1995 M-36982PDF Format

Entitlement to Water Under the Southern Arizona Water Rights Settlement Act (SAWRSA)

11/29/1994 M-36981PDF Format

Implementation of the Oil Pollution Act of 1990 by the Minerals Management Service

05/02/1994 M-36980PDF Format

Secretary’s Authority for Creating the National Biological Survey

10/04/1993 M-36979PDF Format

Fishing Rights of the Yorok and Hoopa Valley Tribes

01/11/1993 M-36975PDF Format

Governmental Jurisdiction of Alaska Native Villages Over Land and Nonmembers